Directed assembly of braided, woven or twisted wire

ABSTRACT

Wires, such as microwires or nanowires are braided, woven or twisted by attaching an end piece to a first end of a plurality of wires, wherein the end piece has a response to an electromagnetic or fluidic work force different than that of the wire. The end pieces are manipulated relative to each other by selective application of electromagnetic or fluidic force that braids, weaves or twist the wires at the first end, while the second ends of each of the wires remain fixed relative to each other.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 62/211,139, filed on Aug. 28, 2015. The entire teachings of the above applications are incorporated herein by reference.

GOVERNMENT SUPPORT

This invention was made with government support under contract FA8650-15-7543 from the Air Force Research Laboratory. The government has certain rights in the invention.

BACKGROUND

Radiofrequency (RF) systems, such as cell phones and geo-positioning systems (GPS) employ micro circuitry that includes wire connectors having diameters as small as a few nanometers. At the same time, energy storage and such systems is limited and, therefore, loss of energy, such as through electrical heat loss, are significant, thereby further limiting utility and ability to scale down the size of such devices.

One option for reducing electrical heat loss from wires is to braid or twist them, whenever possible, so that are in relatively close proximity to each other. However, wires on such a small scale are not only difficult to manufacture, but are extremely fragile and have a limited ability to bend. Further, the size of wires on a nano- and micrometer scale are difficult to manipulate, once fabricated, and are extremely susceptible to failure.

Therefore, a need exists for a method of assembling nano and micrometer-scale wires in a braid, weave or twist that overcomes or minimizes the above-referenced problems.

SUMMARY OF THE INVENTION

The invention generally is directed to a method of weaving a braided, woven or twisted wire, typically for use in RF systems, such as cell phones and GPS systems.

In one embodiment, the method of weaving a braided, woven or twisted wire includes attaching an end piece to a first end of each of a plurality of wires, each end piece having a response to an electromagnetic or fluidic force different than that of the wire. Respective second ends of each of the wires are fixed relative to each other, and the end pieces are manipulated relative to each other by selective application of an electromagnetic or fluidic force that braids or twists the wires to thereby weave the braided or twisted wire.

Typically the wire is a microwire, having a diameter in a range of between about 1 μm and about 1 mm. Alternatively, the wire is a nanowire, having a diameter in the range of between about 1 nm and about 100 nm.

The wire is formed of a suitable material, such as a material that includes at least one member of the group consisting of a metal, a ceramic, a polymer, and a glass.

The end piece typically includes at least one member of the group consisting of a dielectric material, a magnetic material, a metallic material, and a ferro-electric material. In one specific embodiment, the end piece is formed of a dielectric material that is an electret.

The end piece in one embodiment is a bead. Alternatively, the end piece can be a spool of the wire that is braided, woven or twisted by the method of the invention.

Examples of suitable electromagnetic forces that can be employed to manipulate the end pieces typically include at least one member of the group consisting of an electrostatic force, a magnetostatic force, an electroquasistatic force, and an optical electromagnetic field.

Examples of suitable fluidic forces that can be employed typically includes at least one member selected from the group consisting of pressure, a concentration gradient, a thermal gradient, and an electrogradient.

In one embodiment, the end pieces are selectively manipulated by use of an addressable platform that controls an electromagnetic force to which the end pieces are exposed. The beads or spools move relative to each other by responding to selective application of a force from, for example, an addressable platform, thereby braiding, weaving or twisting the wires to which the end pieces are attached.

This invention has many advantages. For example, by braiding, weaving or twisting the wires, electrical heat loss in the wires during use and or assistance is significantly reduced, thereby resulting in better performance and greater durability of electrical systems in which they are employed. In addition, braiding, weaving or twisting of the wires by the method of the invention can be done rapidly and at a very low rate of failure. Braiding, weaving, or twisting also provides high mechanical strength while preserving mechanical flexibility.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.

FIG. 1 is an example of one embodiment of a two-dimensional addressable platform for directed-assembly of braided, woven or twisted wire according to the method of the invention.

FIG. 2 is another embodiment of an addressable platform.

FIG. 3 is a perspective view of one embodiment of a device for conducting the method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

A description of example embodiments of the invention follows.

The invention generally is directed to a method of weaving a braided or twisted wire for the use in RF systems, such as cell phones and GPS systems.

“Braiding,” as that term is understood herein, means plaiting or interweaving a continuous length of material to form a braid.

“Weaving,” as that term is employed herein, means interlacing or entwining a continuous material, also referred to herein as a “wire.”

“Twisting” means interweaving or twining a continuous length of material, such as a wire to form a weave of that material.

In one embodiment, the method includes attaching an end piece to a first end of each of a plurality of wires. Examples of suitable wires include microwires and nanowires. In one embodiment, the wire is a microwire, having a diameter in a range of between about 1 μm and about 1 mm. In another embodiment, the wire is a nanowire, having a diameter in a range of between about 1 nm and about 100 nm.

The wires suitable for use in the method of the invention are those typically employed in the fabrication of RF devices or other devices that employ microcircuitry and nanocircuitry. Examples of suitable wires include those that are formed of at least one member of the group consisting of a metal, a ceramic, a polymer, and a glass. Examples of suitable metals include copper, silver and gold. Example of a suitable ceramics is aluminum oxide. An example of a suitable polymer is polyimide. Examples of suitable glasses include silicon dioxide. Examples of suitable nanotubes include those formed of at least one material selected from the group consisting of carbon and inorganic material.

In one embodiment, the wire has a dielectric core, coated by an electrically conductive layer which, in turn, is insulated from its surrounding environment by the dielectric coating.

The end pieces are formed of a suitable material that is susceptible to selective application of an electromagnetic or fluidic force. In one embodiment, the end pieces are all formed of the same material or composition of materials. In an alternative embodiment, the end pieces are each formed of different materials, whereby the end pieces are differentially susceptible to distinct electromagnetic or fluidic forces. Examples of suitable materials are those known to be susceptible to electromagnetic or fluidic force, such as a dielectric material, a magnetic material, a metallic material, and a ferro-electric material. In one specific embodiment, wherein at least a portion of the end pieces are formed of a dielectric material, the dielectric material includes an electret.

In one embodiment, the end pieces have a diameter greater than that of the wire to which they are attached. In one specific embodiment, the end piece is a bead, having a suitable shape, such as that of a sphere. Typically, the bead will have a diameter in a range of between about 30 microns and about 100 microns. Alternatively, the end piece can be in the form of a spool about which the wire to be braided, woven or twisted is wound. In some embodiments, the beads or spools are formed of a uniform material. In an alternative embodiment, the beads or spools are formed in layers having distinct electromagnetic properties. For example, in one embodiment, the beads can include a magnetic core.

In one embodiment, the end piece are beads that are attached to a first end of each of a plurality of wires by a suitable means. In one embodiment, the bead is a metal bead that is attached to a nanowire by a suitable glue, such as a UV-curable epoxy glue. In one specific embodiment each metal bead is attached to a respective first end of the plurality of wires by first affixing each nanowire to the surface of a fluorinated ethylene polypropylene (FEP) sheet. A drop of UV-curable epoxy glue is then applied with a micropipette to the first end of the nanowire and a micromanipulator arm is employed to lower a metal-coated bead onto the bead of UV-curable epoxy glue. UV light can then be employed to cure the epoxy, thereby fixing the bead to the first end of the nanowire.

The second ends of each of the wires are fixed relative to each other. In one embodiment, the wires are fixed at their respective second ends to each other. In an alternative embodiment, the wires are fixed at their respective second ends to a fixed support and are proximate to each other. In either case, the end pieces are suspended by the wires from the point at which the second ends of the wires are fixed to each other or to a separate support by a suitable force, such as gravity.

The end pieces are manipulated by selective application of an electromagnetic or fluidic force that braids, weaves or twists the wires to thereby form the braided, woven or twisted wire. The beads or spools of the end pieces can be manipulated in two dimensions or three dimensions. The end pieces are manipulated relative to each other by suitable means, such as by employing an addressable platform. For example, where the end pieces are manipulated relative to each other by selective application of an electromagnetic force, the selective application of that force can, in one embodiment, be obtained by a planar, or semi-planar grid of patterned electrodes. The patterned electrodes can exist in a single layer or in multiple layers whereby selective actuation of the pattern of electrodes directs the end pieces, whether they be beads or spools, or some other configuration, across the patterned surface relative to each other in a manner that causes the wires to which the end pieces are attached to form a braided, woven or twisted wire.

The platform of electrodes, in turn, is fabricated by a suitable method, such as by photo lithography. Examples of suitable materials to fabricate an addressable platform can be found, for example, in Zemánek, et al., “Dielectric actuation strategy for micromanipulation along complex trajectories.” IEEE/ASMI Int'l. Conf. on Advanced Intelligent Mechatronics (AIM) (2014), the relevant teachings of which are incorporated herein by reference in their entirety. FIGS. 1 and 2 represent examples of addressable platforms of patterned electrodes 10, 12, respectively, that can selectively manipulate end pieces suspended above them by the wires to be braided, woven or twisted. FIG. 2 is a representation of a “walk-through” pattern, and FIG. 3 is a representation of a “walk around” pattern.

In one embodiment, the wires are all fixed relative to each other at a constant distance from the grid providing selective application of electromagnetic force, as shown in FIG. 3. As shown therein, addressable platform 13 includes base 14 and patterned electrodes 16. End pieces 18 are attached to wires 20 that, in turn, are fixed to a single point 22. Patterned electrodes 16 are in electrical communication with computer 24 through wires 26. Computer 24 thereby controls the pattern of electromotive force at patterned electrodes 16 to thereby manipulate end pieces 18 in a plane above addressable platform 13 and, as a consequence, braids wires 14 to form a single braided, woven or twisted wire extending from single point 22. In an alternative embodiment, wires 20 are wound around spools that are fixed in a plane at a constant distance from the grid. The spools are manipulated in position relative to each other by a selective application of electromagnetic force of the grid, thereby causing the wires to form a braided, woven or a twisted wire. As the point at which the second ends of the wires are fixed relative to each other is drawn away from the grid, the wires are unwound from the spools as braiding, weaving or twisting of the wires progresses.

The teachings of all patents, published applications and references cited herein are0 incorporated by reference in their entirety.

While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. 

What is claimed is:
 1. A method of forming a braided, woven or twisted wire, comprising the steps of: a) attaching an end piece to a first end of each of a plurality of wires, the end piece having a response to an electromagnetic or fluidic force different than that of the wire; b) fixing respective second ends of each of the wires relative to each other; and c) manipulating the end pieces relative to each other by selective application of an electromagnetic or fluidic force that braids, weaves or twists the wires to thereby form the braided, woven or twisted wire.
 2. The method of claim 1, wherein the wire is a microwire, having a diameter in a range of between about 1 μm and about 1 mm.
 3. The method of claim 1, wherein the wire is a nanowire, having a diameter in a range of between about 1 nm and about 100 nm.
 4. The method of claim 1, wherein the wire includes at least one member of the group consisting of a metal, a ceramic, a polymer, and a glass.
 5. The method of claim 1, wherein the end piece includes at least one member of the group consisting of a dielectric material, a magnetic material, a metallic material, and a ferroelectric material.
 6. The method of claim 5, wherein the dielectric material is an electret. The method of claim 1, wherein the end piece has at least one dimension greater than that of the wire diameter.
 8. The method of claim 7, wherein the end piece is a bead.
 9. The method of claim 7, wherein the end piece is a spool of the wire.
 10. The method of claim 1, wherein the wires are fixed at their respective second ends to each other.
 11. The method of claim 1, wherein the wires are fixed at their respective second ends to a fixed support and are proximate to each other.
 12. The method of claim 1, wherein the end pieces are manipulated by manipulation of an electromagnetic force.
 13. The method of claim 12, wherein the electromagnetic force includes at least one member of the group consisting of electrostatic force, magnetostatic force, electroquasistatic force, and optical force.
 14. The method of claim 1, wherein the end pieces are manipulated by manipulation of a fluidic force.
 15. The method of claim 14, wherein the fluidic force includes at least one member selected from the group consisting of pressure, concentration gradient, thermal gradient, and electrowetting.
 16. The method of claim 1, wherein the electromagnetic or fluidic force is manipulated in two dimensions.
 17. The method of claim 1, wherein the end pieces are manipulated by selective application of an electromagnetic force from an addressable platform.
 18. The method of claim 1, wherein the electromagnetic or fluidic force is manipulated in three dimensions.
 19. The method of claim 1, wherein the wires are braided.
 20. The method of claim 1, wherein the wires are woven.
 21. The method of claim 1, wherein the wires are twisted. 